| 时间 | 平均 | 最高 | 最低 |
|---|---|---|---|
| 2025 | 1.5 | 1.65 | 1.41 |
| 2024 | 1.53 | 1.85 | 1.15 |
| 2023 | 1.11 | 1.27 | 0.95 |
| 2022 | 0.99 | 1.1 | 0.87 |
| 2021 | 0.98 | 1.11 | 0.87 |
| 2020 | 1.2 | 1.47 | 0.99 |
| 2019 | 1.06 | 1.2 | 0.95 |
| 2018 | 1.26 | 1.54 | 0.97 |
| 2017 | 1.81 | 2.4 | 1.45 |
| 2016 | 3.02 | 4.49 | 2.23 |
| 2015 | 2.86 | 3.52 | 2.1 |
| 2014 | 2.35 | 2.83 | 2.1 |
| 2013 | 2.38 | 2.83 | 1.95 |
| 2012 | 2.31 | 3 | 1.63 |
| 2011 | 7.05 | 20.92 | 1.93 |
| 2010 | 10.19 | 12.49 | 7.05 |
| 2009 | 6.39 | 8.08 | 4.17 |
| 2008 | 6.28 | 11.39 | 3.27 |
| 2007 | 7.74 | 11.81 | 4.24 |
| 2006 | 4.68 | 5.79 | 4.02 |
| 2005 | 4.73 | 5.76 | 3.78 |